Signaling system



July 29, '1941. i F. E. WELD SIGNALING SYSTEM Filed May 5, 1939 I5Sheets-Sheet l m E, Q wil@ \N 0 NI .II Y Ow wlmk'@ 1% C, e8. mi D JM mmhn Nw l b mw L EN QS A @QN .ww mm, W

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WLness July 29, 1941. F. E. WELD SIGNAMNG SYSTEM Filed May 5, 1939 3Sheets-Sheet 2 vuil# ..0 IN m mw@ @L T@ lmvl@ @n Y @MQ l July 29, 1941.F. E. WELD y SIGNALING SYSTEM Filed May 5, 1939 5 Sheets--Shee'l 5 .wn WV@ W @LN T ww nmnml@ Gm X Mw ,WL m QUIIIM Patented July 29, 1941Gamewell Company, Mass., a corporation of ltlassachusettsv ApplicationMay 5, 1939i, Serial No. 271,925

14 Claims.

The present invention relates to signaling systems, and moreparticularly to systems of the general type disclosed in the BridgesPatent No. 2,201,712, granted May 21, 1940.

The Bridges patent discloses a multiple circuit repeater systemparticularly useful for re alarm service. The system not only affordsfull noninterfering operation, but has reliable protective facilitiesfor automatically maintaining all normal circuits in operative conditionafter the occurrence of a break in any circuit. In particular, onefeature of the Bridges system is that the protective equipment involvesthe use of only a single timing relay for the whole system, and normalsignaling operation is in no way dependent on the timing relay.

The principal object of the present invention is to provide improvementsin the Bridges system with the particular View of maintaining theability of the system to formulate, transmit and repeat signals, evenfrom a circuit in which a break may exist. In the best form of theinvention yet devised a faulty circuit, instead of being isolated fromthe rest of the system, is automatically conditioned for Signalingthrough an emergency conductor, preferably ground, while the capacity ofthe system for non-interference is substantially maintained.

Other features of the invention consist of certain novel circuitarrangements hereinafter described and particularly defined in theclaims.

In the accompanying drawings Fig. 1 is a diagram of the preferred systemin normal inactive condition; Fig. 2 is a diagram similar to Fig. 1 butillustrating the operation of the system during transmission of asignal; and Fig. 3 is a diagram illustrating the emergency conditioningof a faulty circuit.

General description The invention is herein described as embodied in arepeater type fire alarm system having a number of signaling circuits.For simplicity, only two circuits are shown in the drawings, althoughthe invention is applicable to a system having an number of circuits.The signaling circuits are indicated as box circuits Cl and C2. Thoseparts of the box circuits which are local to the central station areindicated in double lines in the drawings, and each is connected atterminals, designated Line and Line, to the outlying lines. The linesexternal to the central station include a number of boxes in series,designated N, of the non-interfering and succession type,

Newton Upper Falls,

and capable of signaling through ground as will hereinafter bedescribed.

Each box circuit includes a line battery 20 and a normally energizedmain line relay. The two main line relays are indicated at M1 and M2.Associated with each b'ox circuit are a repeater relay (R1, R2) and anautomatic grounding relay (G1, G2). Each relay has a number of contactswhich are shown in the drawings directly under the corresponding relaywinding. Each main relay has seven contacts numbered from lato 7, ofwhich contacts I, 4 and 6 are movable. Contacts 3, 4 and 5 correspond tothe main relay'contacts of the Bridges patent above referred to, themovable contact 4 being normally closed on contact 3 and adapted tocloseon contact` when the relay Mis deenergized. Contacts l, 2 arenormally open and are adapted to close when the relay is deenergized, tocontrol the operation of the grounding relay as will hereinafter bedescribed. Contacts 6 and 'l control the operation of a trouble bell. Y

Each repeater relay hasten contacts, numbered from I lll to lill, ofwhich contacts 103, IM, |08 and IUS are movable. Contacts Ill, |01 and|08 correspond to the repeater relay contacts of the Bridges patent.Contacts Ill! to m5 are for controlling the operation of the systemunder abnormal conditions, while contacts |69 and H0 are included in thetrouble bell circuit.

Each grounding relay has twelve contacts, numbered from 2U! to 2l2, theoperation of which will be hereinafter described.

The box circuit Clin normal condition is traced as follows: Startingwith the positive terminal of the battery 20, the circuit includes thewinding of the main line relay M1, a wire 22 leading to the terminaldesignated Line, through the series boxes N of the outlying line to theterminal designated Line, a wire 24, contacts lll?, |26 of the repeaterrelay R1, a wire 26, contacts 2H), 29 of the grounding relay G1, andfinally a wire 28 back to the negative side of the battery 20.

The movable contact |08 of the'repeater relay is connected to a resistor30, which in turn is connected to the line 22' by a wire 32. As intheabove-mentioned Bridges patent, when the repeater relay is energized,contacts'lll', |06 are closed and contacts |05, |01 are opened, therebyopening the box circuit and establishing a shunt energizing circuit forthe main line relay M1 through the resistor 30.

The movable contact A of the main line relay is connected by a wire 34with the movable repeater relay contacts |03 and |04, which areelectrically connected together. The fixed contact |05 on which |04 isnormally closed, is connected by a wire 36 with a repeater bus RB. Themain line relay contact 5 on which contact 4 closes when the relay M isdeenergized, is connected to the positive side of a local battery 31.The local battery serves for all central station connections of theseveral circuits and its terminal-s are simply designated by plus andminus signs in circles, the actual connections to the terminals beingomitted to avoid complieating the diagram. It will be observed that whenthe main relay is deenergized, the repeater relay being at the same timedeenergized, the positive side of the loc-al battery is connected to therepeater bus through contacts 5, 4, wire 34, contacts |04, |05 and Wire36. These latter connections, as well as the repeater bus RB, constitutea repeater circuit which is shown in heavy lines.

Upon energization, the repeater relay opens the normally closed contacts|04, |05, closes the normally open contacts |0I, |03 and opens thenormally closed contacts |0|, |02. Contact |0| is connected by a Wire 38with one side of the repeater relay Winding R', the other side of whichis connected to the negative terminal of the local battery. Contact |0|is also connected by a wire 40 Ywith contact 3 -of the main line relay.

The grounding relay G1 is adapted, under abnormal conditions caused by abreak in the box cir-cuit, to connect the terminals Line and Linetogether and to ground the negative terminal of the box circuit battery20. One side of the grounding relay is connectedto the negative terminalof 'the local battery and the other side is connected by a wireV 42 withcontact A lamp 44 in parallel to the relay G1 serves -to indicate whenthe relay is energized. Movable contact 203, which is Vadapted to closeon 20| when the relay G1 is energized, is connected to the positiveterminal of the local battery. Closure of contact 203 on 20| openscontacts 20|, 202, the latter being connected by a wire 4 6 with thefixed contact 204. The movable contact 205 which is adapted to close on204 when the relay G1 is energized, is connected by a Wire 48 with thexed contact |02 of the repeater relay. Movable contact 206 connects by awire 50 with the repeater relay contacts |03 and |04, and the iixedcontact 201 on which 206 is normally closed, is directly connected tothe wire 36 which connects with the repeater bus.

The normally closed contacts 209, 2|0 are, as previously described,included in the box circuit. When the relay G1 is energized, contacts209, 2 l0 open and 209 closes on 208, the latter being connected toground as indicated at 52, thus establishing a direct connection betweenthe negative terminal of the line battery 20 and ground. The fixedcontact 2| is directly connected .to the Line terminal and the movablecontact 2|2 is connected to the wire 32 which connects with the Lineterminal, so that when contacts 2l I, 2| 2 close, due to energization ofthe grounding relay, the two terminals of the outlying line areconnected together,

Contact 202 is connected by a wire 54 with the movable contact of themain line relay. "f -Contact 2 is connected by a wire 56 with a busdesignated as a restore bus X. A trouble bell busTBB is connected by alead 58 through contacts |09, ||0, a Wire 60 and contacts 1, 6 to thepositive terminal of the local battery. The bus includes a bell 62connected to the negative terminal of the local battery so that thecircuit for the bell is closed when contacts |09, I0 and 1, 6 areclosed.

The second circuit C2 and all other box circuits which may be includedin the system are identical with the circuit C1 above described, and areconnected to the several busses in the same manner.

A single delayed closure timing relay T has its winding connectedbetween the negative terminal of the local battery and the repeater busRB. The contacts 64 of the timing relay are normally open and areadapted' to close only if the timing relay remains energizedcontinuously for greater than a predetermined time, which is adjusted tobe longer than the longest time of box circuit opening of any normalsignaling operation. When the contacts 64 close, a connection isestablished between the positive terminal of the local battery and therestore bus X through a lead 65.

The system may be provided with suitable signal manifesting devices tooperate in the usual manner, illustrated diagrammatically in Fig. 1 as agong A and a register B connected between the repeater bus RB and thenegative terminal of the local battery.

The various operations of the system under different conditions will nowbe described.

System inactive When the system is in normal condition, all boxes beinginactive, each box circuit forms a closed loop and the several main linerelays are continuously energized, thus holding their movable contactsattracted. The repeater relays and the grounding relays are deenergized.'Ihis condition of the system is shown in Fig. 1.

Box signaling over normal system During a code signaling operation by anactive box in one of the box circuits, say circuit C', the circuit issuccessively opened and closed by the action of the code wheel. Upon therst opening of the circuit by the code wheel, the main line relay M isdeenergized and its movable contacts I, 4 and 6 retract. The closure ofcontacts 6, 1 simply operates the trouble bell, and the closure ofcontacts 2 is of no importance at this time. The closure of Contact 5, 4energizes the repeater relay R2 of the box circuit C2 as can be seen byfollowing the circuit shown in heavy lines, from the positive terminalof the local battery through contacts 5, 4 of main line relay M, wire34, contacts |04, |05 of repeater relay R, wire 35, repeater bus RB,thence through wire 36 of circuit C2, contacts |05, |04 of repeaterrelay R2 (also contacts 201, 206 o-f grounding relay G2 and wire 50),Wire 34, contacts 4, 3 of main line relay M2, and wires 40 and 33through the repeater relay R2 to the negative terminal of the localbattery. The repeater relay R2 of circuit C2, being thus energized,attracts its contacts, thereby opening box circuit C2 at |06, |01 andestablishing a shunt circuit for the main line relay through resistor 30and contacts |08, |06. The repeater relay R1 of circuit C1, however,remains deenergized since the main line relay contacts 3, 4 are nowopen.

The result of opening the box circuit C1 by the formulation of a signalin the circuit, is that the inactive circuit C2 and, in fact, any otherinactive box circuits of the system, are likewise opened and the mainline relays of the inactive circuits are maintained energized. Thiscondition of the system is shown in Fig. 2.

Upon closure of circuit C1 by the normal action of the code wheel of theactive box, its main line relay is again energized, the contacts areattracted and the connection between the positive battery terminal andthe repeater bus is broken at contacts 4, 5, thereby deenergizing therepeater relay R2 of the circuit C2 and restoring its contacts tonormal. The restoration of the repeater relay contacts of circuit C2also opens the shunt circuit through the resistor 30, and at the sametime closes the box circuit. The entire system is thus restored to thecondition of Fig. 1.

Subsequent opening and closing of the circuit C1, due to formulation ofa code signal by an active box therein, result in a repetition of theoperations above described. All inactive box circuits therefore open andclose in unison with the first box circuit to gain control of thesystem. The boxes are of the non-interfering and succession type, andconsequently the entire system is completely free of the possibility ofinterference between boxes. The particular box construction forms nopart of the present invention, since various types of non-interferingboxes may be employed, such boxes usually operating on the principlethat a box is unable to formulate a signal if it looks into an open linewhen its own contacts are closed.

During a code signaling operation, the time relay T and the manifestingdevices A and B, being connected to the repeater box RB, are energizedon each opening of any box circuit. For any signaling impulse, however,the relay T is not continuously energized for a sufficient time to causeclosure of its contacts 64, and the time relay does not enter into anynormal signaling operation.

As thus far described, the system operates similarly to the system ofthe Bridges patent. It will be noted that the repeater relay contacts tocorrespond to the lockout relay contacts of the Bridges system, but arehere combined with the repeater relay instead of being operated by aseparate relay. As will be shown presently, these contacts, in'combination with the contacts of the grounding relay, operate underabnormal conditions in a fashion similar to the lockout relay contactsof the Bridges system. Under normal signaling conditions, however, theonly repeater relay contacts which are effective to perform any functionare the contacts |05, |01 and |08. The lockout contacts |0| Vto |05 ofthe repeater relay, although they may be attracted and retracted duringa normal signaling operation, perform no function. Contact |02 is inseries with the normally open grounding relay contacts 204 and 205,while contacts |04 and |05 are in parallel with the normally closedcontacts 206 and 201. Thus, so long as the grounding relay remainsdeenergized, any operation of contacts |0| to i 05 is unimportant.

Operation ofpotective devices The occurrence of a break in any boxcircuit does not disable the system, but permits all except the faultybox circuit to be restored to normal, and also converts the faultycircuit for emergency signaling through ground. This operation isdescribed as follows:

Upon a breakin circuit C', for example, its main line relay M', isdeenergized andy the repeater relays of all inactive circuits -areenergized in the same manner as if theY circuit were opened by an activebox. The system then assumes the condition of Fig. 2. After apredetermined time, however, the timing relay allows its contacts 64 toclose, thereby connecting the positive terminal of the local batterywith the restore bus X through the lead 66. The grounding lEnergizationof the. grounding relay occurs 'only for circuit C'. The grounding relayG2 of circuit C2 is not energized because the main line relay contactsI, 2 of that circuit are open.

When the grounding relay Gr'l is energized, its movable contacts 203,205, 206, 209 and 2|2 are attracted and, as previously described, thenegative side of the battery 20 is connected to ground through contacts209, 209, and the positive and negative terminals of the lineareconnected together through contacts 2| l, 2|2. Thus, the box circuitC' now consists of two outlying lines, each running to the break.

When the grounding relay G is energized, a holding Ycircuitisfestablished from the positive side of the local battery throughcontacts 203, 20| and at the same time contacts 202, 20| are opened. y

Energization of the grounding relay G results in energization of therepeater relay R ofthe faulty box circuit. Bearing in mind that thepositive potential of the local battery is applied to contact 202through the circuit previously traced, a circuit may now be continuedfrom contact 202 through lead 06, contacts 204, 205, wire 48, contacts|02, |0| of the repeater relay R', and wire 30 through the repeaterrelay winding to the negative local battery terminal. Contacts 204, 205might be omitted and the wire 40 might be connected direct to contact|02, so that relays R and G' would be simultaneously energized, exceptthat it is desirable to insure that G' shall energize before R'; if R'should pick up its contacts first, the main line relay might beenergized through the shunt resistor 30 before G' could open the circuitat 209, 2|0. Energization of the repeater relay opens contacts |02, I0but a holding circuit for the repeater relay is established from thepositive battery terminal, through contacts 5, 4 of the main line relayM', wire 34 and contacts |03, I 0| of the repeater relay. As a result ofthe energization of the repeater relay, contacts |00, |00 are closed andcontacts |06, |01 are opened, but this is of no importance since the boxcircuit loop is already open at contacts 209. 2|0.

Since both the repeater relay R' and the grounding relay G' are nowenergized, the heavy At the same time the timing relay T is deenergizedand its contacts are allowed to open.

Another effect of the energization of the repeater relay R is to openthe trouble bell circuit at contacts |09, ||0.

The conditionof the system following the operation above describedis'illustrated in Fig. 3. It

will be observed that the lockout contacts |l to |05 of the repeaterrelay R' perform the same general function as the lockout relay contactsof vthe Bridges system, namely, that of isolating the main line relaycontacts of the faulty circuit from -th'e repeater bus, so that thefaulty circuit can neither affect, nor be affected by the repeaterconnection. 'Ihis action occurs only because the -grounding relay 'G' isalso energized, so that the lconnection 36 is broken both at contacts201, 206 .and |05, |04. Ihe correlation of grounding relay and repeaterrelay contacts thus makes it possible to combine the repeating, lockoutand grounding functions into two relays. In spite of the fact that thesystem is adapted for automatic emergency conditioning, the number ofrelays is thus held to three for each circuit.

It is to be noted that the isolation of the faulty circuit C from therepeater'bus occurs only during continued deenergization of the mainline relay M, since the holding circuit for R is carried throughcontacts 4, 5. As will be shown presently, when the relay M becomesenergized, as at the start of a ground signaling operation, the faultycircuit is no longer isolated from the system.

Boa: signaling over the system conditioned as shoumfn Fig. 3

When t-he system is conditioned as in Fig. 3, dueto` operation of thegrounding relay on a faulty box circuit, the normal box circuit C2 andany other normal box circuits of the system stand ready to originate andtransmit signals, and

cuits, and this will b'e done by describing, first,

the effect on a normal circuit Vof a'sgnal originating in the faultycircuit, and, second, the effect on the faulty -circuit of a signaloriginating in a normal circuit.

Assume first that with the system as shown in Fig. 3, a box in thefaulty circuit C starts to formulate a signal. 'I'he boxes are of a typeto transmit emergency signals through ground, for which purpose severaltypes of boxes are available. The preferred type of box is the so-calledthreefold box 'described in the Beach Reissue Patent 20,449, whichincludes means fortesting the line and `establishing an emergency groundsignaling connection on the -second round, if the line is found to beopen. Whatever type of box is employed, a connection is firstestablished to ground prior to the signal formulating operation. Aclosed circuit may now be traced from ground through wire 52, contacts208, 209 of the grounding relay G', wire 28, battery V20, mainline relayM', Wire 22, to terminal Line, wire 32 and contacts 2|2, 2|| of relay Gto the terminal Line," then from one or the other of the line terminalsto the box, and finally to ground at the box. The main line relay M isthen energized and its contacts are attracted, thereby breaking theholding circuit for the repeater relay R' at the contacts 4, 5. Onsubsequent opening and closing of the ground signaling circuit throughthe action of the code wheel, the main line relay is successivelydeenergized and reenergized in exactly the same manner as if the signalwere being transmitted over a normally closed loop. The repeater relayR1, having been deenergized by the breaking of its holding circuit,remains deenergized during the entire signaling operation. Therefore,upon each deenergization of the main line relay, due to opening of theground signaling circuit by the action of the code wheel, the connectionbetween the positive terminal of the local battery and the repeater busRB is established through contacts 5, 4, wire 34, contacts |04, |05, andconnection 36, just as in the case of normal signaling. Accordingly,signals originating from any box in the faulty circuit are repeated overall normal box circuits in the lsystem and thus interference with anyactive box in circuit C1 by a box in any other circuit is prevented.

At the conclusion of the signal the ground connection at the box isbroken and the main line relay is deenergized. It is now necessary toreenergize the repeater relay R1 in order to permit all normal boxcircuits to be restored to normal condition. This is accomplished by theaction of the timing relay operating through the restore bus X. In otherwords, the timingrelay and the repeater relays of' the several circuitsgo through the same operations a's they did' immediately following thedetection of the break in the faulty box circuit. The grounding relay G1of the faulty -circuit remains -energized throughout, because of theholding circuit established at contacts 20|, 203.

Assume now that with the system in the condition of Fig. 3, a box in thenormal circuit C2 starts to formulate a signal. In this case there is noeffect on the faulty circuit C1 because the connection for circuit C1which leads from the repeater bus RB terminates on the open contacts 201of the grounding relay G1 and |05 of the repeater relay R1. Hence, whilea signal originating in the faulty circuit can repeat into all normalcircuits, the reverse is not true and a signal originating in a normalcircuit cannot repeat into the faulty circuit. Interference will,therefore, occur if a box in the faulty circuit is pulled while a box ina normal circuit is transmitting a signal. This contingency is remoteand even if it does occur, it will ultimately result in circuit C1taking control of the system, even though there may be some initialjumbling of the signals. This follows from the general proposition thata box or circuit having good non-interference characteristics will losecontrol to a box or circuit of poorer non-interference characteristics;that this proposition holds in this specific case may be seen byconsidering that in the normal operation of the code 'wheels a time mustcome when the main line relay M1 is deenergized and the main line relayM2 is energized. At such a time the repeater circuit to the repeaterrelay R2 is closed and the energization of the repeater R2 under suchYcircumstances results in opening the box circuit C2 and thus cuts theactive box of circuit C2 out of further participation. It will be notedthat circuit C2 is unable to prevent circuit C1 from gaining controleven at a time when relay M2 is deenergized and relay `M1 is energized,because the consequent energization of repeater relay R1 has no'eifecton circuit C1. The result is therefore that 'the box in the faulty'circuit takes control at some time in the round. One round may bejumbled, but a clear signal is thereafter transmitted by the active boxin the faulty circuit. After such box has completed its signal thesystem is restored to the condition of Fig. 3 through the operation ofthe timing relay, and thereafter the waiting box in the -normal circuit,if it is of the succession type, will formulate and transmit its ownsignal.

The foregoing method of operation is considered the preferred method, inspite of the possibility of jumbled signals under unusual circumstances.If desired, however, the faulty circuit Ymay be eifectually isolatedfrom the remainder of the system by providing a manual switch B3 in eachlead 36. After a box circuit has been found faulty, the switch 63 may beopened manually, thus making it impossible for the faulty circuit toaffect or to be affected by any of the other circuits. It is, however,considered preferable to allow the faulty circuit to participate in theoperation of the system as a whole, even at the risk of occasionaljumbling, than to isolate the faulty circuit from the rest of thesystem.

Restoration of circuit after repair After the break in the faulty boxcircuit has been repaired, the circuit isl restored to its normal loopcondition manually, by momentarily opening a switch 68 in series withthe contact 203 of the grounding relay G. This opens the holding circuitand deenergizes the grounding relay. Movement of contact 209 to 210 andof 2|| to 212 closes the circuit of the main line relay M through theshunt resistor 3i), it being understood that contacts |06, |08 are nowclosed and contacts |06, 101 are open, due to energization of therepeater relay. Consequently, the main line relay is energized throughthe shunt resistor 30 and its contacts are attracted. The attraction ofthe main relay contacts breaks the holding circuit for the repeaterrelay at 4, 5. The repeater relay then becomes deenergized, and thecircuit is restored to the normal condition shown in Fig. 1.

It will be noted that on opening the manual switch 68, contacts 206, 201of the grounding relay will close before contacts 5, 4 of the main linerelay open. A connection is then momentarily established from thepositive terminal of the local battery through contacts 5, 4, wire 34,wire 50, contacts 206, 201 and wire 36 to the repeater bus. Thismomentary connection will tend to cause the repeater relays of normalcircuits to be energized and give a stroke on the system. To preventthis, a switch 'l0 is preferably included in the lead 63 and is adaptedto be opened simultaneously with the manual switch 68.

Conclusion -From the foregoing description it will be seen that thesystem is in general similar to that of the Bridges patent, in thatperfect non-interference between normal circuits is obtained.

Furthermore, the reliability of the system is enhanced by the provisionfor automatic emergency conditioning of a faulty circuit, instead ofrendering such circuit inoperative. This result is attained withoutserious loss of non-interfering characteristics, since as previouslydescribed, the only possibility of interference arises when a box in thefaulty circuit starts to operate during a signal formulation by a box ina normal circuit.

As in the Bridges system, the protective devices have the importantadvantage of being dependent on a single timing relay which in no wayenters into any signaling operation. Failure of the timing relay or itsconnections can result only in a lossV of protective function and cannotdeprive the signaling circuits, so long as they are in normal condition,of their ability to signal and repeatin normal fashion. l

Although the invention has been illustrated and described as embodied ina fire alarm system, it is to be understood that the invention is notthus limited, but may be applied to signaling systems for otherpurposes. Furthermore, the invention is not to be considered as limitedto the particular embodiment shown and described but may be modiedwithin the scope of the claims.

Having thus described the invention, I claim:

l. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, repeater means for the several circuits, a grounding relay foreach signaling circuit to condition the circuit for emergency groundsignaling, timing means acting upon deenergization of a main line relayfor a predetermined time to Operate the grounding relay of thecorresponding circuit, and lockout means operated by the timing means toisolate said circuit from the repeater means during continueddeenergization of the main line relay. Y

2. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, repeater means for the several circuits, a grounding relay foreach signaling circuit to condition the circuit for emergency groundsignaling, timing means acting upon deenergization of a main line relayfor a predetermined time to operatethe grounding relay of thecorresponding circuit, a lockout device for each circuit, andconnections between the timing means and the lockout devices to isolatean abnormal circuit from the repeater means during continueddeenergization of the main line relay.

3. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, repeater means for the several circuits, a grounding relay foreach signaling circuit to condition the circuit for emergency groundsignaling, a single timing relay for the several circuits operable upondeenergization of any main relay for a predetermined time, a lockoutdevice for each circuit, and connections between the timing relay, thegrounding relays and the lockout devices to energize the grounding relayof an abnormal circuit and also to isolate the abnormal circuit from therepeater means during continued deenergization of the main line relay.

4,'A'signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, a repeater relay for each circuit, a repeater bus connecting themain line relays and repeater relays of the several circuits, agrounding relay for each circuit to condition the circuit for emergencyground signaling, timing means acting upon deenergization of a main linerelay for a predetermined time to operate the grounding relay of thecorresponding circuit, and lockout means operated by the timing means toisolate vsaid circuit fromthe repeater bus during continueddeenergization of the main line relay.

"5. A signaling system having in combination bus connecting the mainline relays and repeater Arelays of the several circuits, a groundingrelay foreach circuit to condition the circuit for emergency groundsignaling, a 'single timing relay for the several circuits operable upondeenergization of any main line relay for a predetermined time, a`lockout device for each circuit, and connectionscontiolled by the timerelay to operate' the grounding relay and also, during continueddeenergization of the main line relay, to isolate the abnormal circuitfrom the repeater bus.

v`6. rA signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, a repeater relay and a groundingrelay for each signaling circuit,each grounding relay having provision for converting its circuit foremergency ground signaling, a repeater circuit, timing means operatingupon de-energization of a main line relay for a predetermined time foroperating the grounding relay of its circuit, while leaving the othercircuits in normal condition, and lockout means for isolating a faultysignaling circuit from the repeater circuit.

7. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, a repeater relay and a grounding relay for each signalingcircuit, each grounding relay having provision for converting itscircuit for emergency ground signaling, a repeater circuit, a singletiming device for the several circuits, connections between the timingdevice and the grounding relays to operate the grounding relay of anycircuit for which the main line relay remains de-energized for apredetermined time, and lockout means for isolating a faulty signalingcircuit from the repeater circuit.

8. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, a repeater relay and a grounding relay for each signalingcircuit, each grounding relay having provision for converting itscircuit for emergency ground signaling, a repeater circuit, the mainline relays having contacts connecting With the repeater circuits,lockout means for opening the connections between the several main linerelay contacts and the repeater circuit, and timing means operated upondeenergization of a main line relay for a predetermined time foroperating the grounding relay and lockout means of the correspondingsignaling circuit.

9. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, a repeater relay for each signaling circuit having contacts toopen its signaling circuit, a repeater bus, each main line relay havinga contact connected with its corresponding repeater relay and a contactconnected With the repeater bus, lockout means for opening theconnection between the main line relay contact and the repeater bus,time actuated means, additional main line relay contacts, andconnections from the time actuated means through the additional mainline relay contacts to operate the lockout means for any circuit forwhich the main line relay remains open for a predetermined time,

10. A signaling system having in combination a plurality ofnormallyclosed signaling circuits each having a normally en'ergizedmainVline relay, repeater devices controlled by the signaling circuits, agrounding device for each circuit operable to condition an opensignaling Ycircuit for emergency ground signaling, a time 'relay havingcontacts to *operate only after an abnormal signalingcircuit'remainsopen for a predetermined time, lockout means for eachcircuit, and connections including the time relay contacts to'oper-atethe grounding device of Yan abnormal circuit, said connections havingprovision for operating the lockout means of the abnormal circuit torender the abnormal circuit ineiective to control the repeater devicesduring continued deenergization of the mainline relay of the abnormalcircuit.

11. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay, repeater devices controlled by the signaling circuits, agrounding device for each circuit operableto condition an open signalingcircuit for emergency ground signaling, a time relay having contacts tooperate only after an abnormal signaling circuit remains open for apredetermined time, lockout means for each circuit, connectionsincluding the time rel-ay contacts to operate the grounding device of anabnormal circuit, said connections having provision for operating thelockout means of the abnormalcircuit to render the abnormal circuitineffective to control the repeater devices during continueddeenergization of the main line relay of the abnormal circuit, means forestablishing a holding circuit for the grounding device, and means underthe control of the main line relay for establishing a holding circuitfor the lockout means of the abnormal circuit.

12; A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay and a repeater relay, repeater connections forl actuating therepeater relays of inactive Vbox circuits, a grounding relay andlockoutV means for each circuit, -a timing relay having contactsactuated only by the deenergization of the` main line relay of anabnormal signaling circuit for aA predetermined time, connectionsincluding the time relay' contactsto operate the grounding relay and thelockout means of the abnormal circuit, the lockout means havingprovision for isolating. the abnormal circuit from the repeaterconnections only during continued deenergization of the main line relayof the abnormal circuit.

13. A signaling system having in'combination a plurality of normallyclosed signaling circuits each having a normally energized mainlinerelay 'and normally deenergized vrepeater and grounding relays, thegrounding relays being operable When energized to convert theircorresponding circuits for'emergency ground signaling, repeaterconnections for actuating the repeaterrel'ays of inactive signalingcircuits,`lockout contacts'for each repeater relay to isolate thecorresponding signaling circuit from the repeater connections wheiiltlierepeater relay is energized, atiming relay having 'contacts actuatedupon `deenergiza'tionofl amain line relay of 'an abnormal circuit forapredetermined time, con-V nec'tionsY including the Vtime relay. contacts"for energizing 'the"grounding and repeater 'relays o f the abnormal'circuit, Yand means for holding the repeater' relay o'f the abnormal.circuitv energized only during continued deenergization oi thecorresponding main line relay.

14. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally energized main linerelay and normally rie-energized repeater and grounding relays, thegrounding relays being operable when energized to convert theircorresponding circuits for emergency ground signaling, a repeatercircuit, each main line relay having a contact connected with therepeater circuit, lockout contacts for each repeater relay to open thesaid connection of said main line relay contact with the repeatercircuit when the repeater relay is energized, a time relay havingcontacts actuated Yupon de-energization of a main line relay of anabnormal circuit for a predetermined time, connections including thetime relay contacts for energizing the grounding and repeater relays ofthe abnormal circuit, and means for holding kthe repeater relay of thealonormal circuit energized only during continued cle-energization ofthe corresponding main line relay.

FOSTER E. WELD.

CERTIFICATE OF CORRECTION. Ptent No; 2,250,922. July 29, 19in.

FOSTER E. WELD.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page l,first column, line )46, for the word "an" read' --any-; page 2, firsxtlcolumn, line 5b., for "--Line" read -"+Line"-; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case Vin the Patent Office.

Signed and sealed this 114th day of October, A. D. 1914.1.

Henry Van Arsdale, (Seal) I Acting Commissioner of Patents.

